def no_teen_sum(a, b, c):
  if a >= 13 and a <= 19 and a != 15 and a != 16:
    a = 0
  if b >= 13 and b <= 19 and b != 15 and b != 16:
    b = 0
  if c >= 13 and c <= 19 and c != 15 and c != 16:
    c = 0
  return a + b + c
  